How would you assign an oxidation number to HCl?

2 Answers
Oct 26, 2015

How would I assign individual oxidation numbers to the constituent atoms of hydrochloric acid? Attend.

Explanation:

We have a #H-Cl# molecule; when we break the bond (conceptually!) the 2 bonding electrons are assumed to go to the most electronegative atom, which is #Cl#. So we get #H^+# and #Cl^-#. By definition, the oxidation number is the charge left on the central atom when all of the bonding electrons pairs are broken. Therefore, oxidation number of #H# #=# #+I#, and oxidation number of #Cl# #=# #-I#.

Try doing this for #F-Cl#, #H_2O#, and #CF_4#.

Oct 26, 2015

The oxidation number of hydrogen is #"+1"# and the oxidation number of chlorine is #"-1"#.

Explanation:

The sum of oxidation numbers in a compound is zero. So the oxidation number of the compound #"HCl"# is zero.

In a compound, hydrogen has an oxidation number of #"+1"#.

Since the sum of the oxidation numbers of hydrogen and chlorine must equal zero, the oxidation number of chlorine must be #"-1"#.

#1(+1)+1(-1)=0#

#"H"^(+1)"Cl"^(-1)"#